1. Field of the Invention
The present invention relates to liquid crystal display (LCD) devices. More particularly, the present invention relates to a simplified method of fabricating thin, light-weight LCD devices.
2. Discussion of the Related Art
A typical liquid crystal display (LCD) device includes a liquid crystal module (LCM), a driving circuit that drives the LCM, and a case that covers an exterior of the LCM to prevent the LCM from being damaged by external impact.
The LCM includes an LCD panel, a backlight unit, and a plurality of optical sheets that vertically redirect light emitted from the backlight unit to the LCD panel. The LCD panel generally includes a plurality of liquid crystal cells arranged in a matrix pattern between two substrates. The LCD panel, backlight unit, and optical sheets are integrally combined with each other to prevent light loss. LCMs such as those described above can be used within display devices of notebook personal computers, mobile vehicles, airplanes, and other portable devices.
FIG. 1 illustrates a sectional diagram of a related art LCM.
Referring to FIG. 1, a related art LCM includes an LCD panel 2 having a plurality of liquid crystal cells arranged in a matrix pattern; upper and lower polarizers 42 and 40, respectively, arranged at front and rear surfaces of the LCD panel 2, respectively, wherein the lower polarizer 40 is arranged on a heat conductor 66.
The LCD panel 2 includes a thin film transistor (TFT) array substrate 2a and a color filter array substrate 2b are bonded together and separated from each other by liquid crystal material (not shown). The TFT array substrate 2a includes a lower substrate supporting a plurality of TFTs and signal lines while the color filter array substrate 2b includes an upper substrate supporting a black matrix layer and a plurality of color filters.
The lower polarizer 40 is attached to a rear surface of the TFT array substrate 2a to polarize light emitted from the backlight unit into the LCD panel 2. The upper polarizer 42 is attached to a front surface of the color filter array substrate 2b to polarize light emitted from the backlight unit and transmitted by the LCD panel 2. The lower polarizer 40 is further bonded to the heat conductor 66 via an adhesive 35.
Referring back to FIG. 1, the aforementioned backlight unit includes a lamp 20 to emit light, a lamp housing 10 covering the lamp 20, a light guide panel 24 to convert light emitted from the lamp 20 into planar light, a reflective plate 26 arranged at a rear surface of the light guide panel 24, and a plurality of diffusion sheets 30 sequentially arranged on the light guide panel 24.
Referring to FIGS. 1 and 2, the heat conductor 66 includes a supporting substrate 65, a thermally conductive layer 63 formed on the supporting substrate 65, and a thermally conductive line 61 formed at peripheral areas of the thermally conductive layer 63. The supporting substrate 65 is formed of the same material as the upper/lower substrate of the LCD panel 2 (i.e., glass). The thermally conductive layer 63 is formed of a transparent conductive material such as indium tin oxide (ITO). The thermally conductive line 61 is formed of silver (Ag) material and transmits a voltage generated by an external voltage source (not shown). The thermally conductive layer 63 converts the voltage transmitted by the thermally conductive line 61 into heat and conducts the heat to the LCD panel 2, wherein the conducted heat prevents a temperature of liquid crystal material within the LCD panel 2 from becoming too low.
Specifically, when the LCD panel 2 is exposed to temperatures in the range of about −40 to 0° C., bubbles form within the liquid crystal material of the LCD panel 2. Consequently, the bubbles alter and restrict the anisotropic dielectric characteristics of the liquid crystal material and prevent the LCD panel 2 from displaying pictures properly. Therefore, the voltage transmitted by the thermally conductive line 61 induces a resistive heating phenomenon in the thermally conductive layer 63, allowing the heat conductor 66 to act as a heater and prevent the formation of bubbles within the liquid crystal material of the LCD panel 2.
Use of the aforementioned related art LCM is, however, disadvantageous because the supporting substrate 65 is typically provided as a thick glass substrate. Therefore, both the weight and thickness of the entire related art LCM can be undesirably large. Further, while the heat conductor 66 of the related art LCM is attached directly to the lower polarizer 40 of the LCD panel 2, the heat conductor 66 and the LCD panel 2 must be formed in separate processes and are connected to separate voltage sources. Consequently, methods of fabricating the related art LCM, and an operation of the related art LCM, can become undesirably complex.